Check valve

ABSTRACT

A check valve with a housing having a valve seat, a valve closing member cooperating with the valve seat and an upstream dirt trapping filter, particularly for sanitary water fittings, wherein the dirt trapping filter and housing are of a unitary construction.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national phase of PCT/EP92/00539 filed 10 Mar.1992 and based, in turn, upon Austrian national application A 1354/91filed 5 Jul. 1991.

The invention relates to a check valve with a housing having a valveseat, a valve closing member cooperating with the valve seat and anupstream dirt trapping filter, particularly for sanitary water fittings.

BACKGROUND OF THE INVENTION

There is a general need for devices preventing return flow, for instanceunder conditions of underpressure, in order to prevent the penetrationof air into a supply line, or the return to the supply duct of a liquidwhich had already passed through. With regard to water supplyapplications, there is a large interest in preventing a return flow ofwater into the supply lines, since the water might then lose itsdrinking quality.

In order to prevent such return flows it is known to use check valveswhose movable valve closing members are subjected to spring action inthe direction of a valve seat which is provided in the housing of thecheck valve.

In order to protect the valve control elements against the incursion offor instance Teflon-hemp (packing) residues, chips or similar dirtparticles, which could affect the operational safety of the valve, ithas been long known to arrange dirt trapping filters in water fittings,upstream of the valve control elements, these filters being separatecomponents to be manufactured and mounted separately, which is not onlyexpensive from the point of view of manufacturing and assembly, butfurthermore presents the danger, for instance when the dirt trappingfilter has to be mounted again, especially during repairs, that it willbe left out altogether, thereby after a certain time, leading to thefailure of the check valve.

OBJECT OF THE INVENTION

It is the object of the invention to eliminate this drawback and toprovide a check valve of the aforementioned kind, which can bemanufactured at relatively low cost, can be easily mounted andespecially maintain operational safety, even after being in operationfor a long time.

SUMMARY OF THE INVENTION

This object is achieved by rigidly connecting the dirt trapping filterwith the housing.

Preferably the dirt trapping filter is made in one piece with thehousing.

Further it is advantageous when the dirt trapping filter has a conicalconfiguration and a largest diameter which is smaller than the outerdiameter of the housing.

BRIEF DESCRIPTION OF THE DRAWING

In the drawing the check valve of the invention is illustrated in anembodiment example, namely the figure shows a longitudinal section.

SPECIFIC DESCRIPTION

The check valve according to the invention, can be arranged in thesupply duct of a sanitary mixing faucet, e.g. within the connectionpoint between the "S"-connections and a flow control valve.

As can be seen from the drawing, the housing 1 is made in one piece withthe conically shaped dirt trapping filter 4. At the same time thehousing forms also the valve seat 2, against which the valve closingmember 3 is pressed under the action of spring 6 with the assistance ofseal 5.

As is also apparent from the drawing, the housing 1 has a groove 1areceiving another ring 1b and is of the same outer diameter as acylindrical portion 1c of the housing extending away from the seat 2.The latter has an inner diameter which is the same as the diameter of apassage 1c between the filter 4 and the small diameter portion of thebevel forming the seat 2. The outer diameter of the filter 4, however,is less than the outer diameter of the housing 2.

I claim:
 1. A check valve comprising:a cylindrical housing having anouter diameter; means forming a beveled valve seat in said housing, saidvalve seat having an inner diameter; a frustoconical dirt-trappingfilter formed in one piece with said housing, upstream of said seat andhaving a large end facing said housing and of an outer diameter lessthan said outer diameter of said housing and an inner diameter equal tosaid inner diameter of said valve seat, said housing having a passage ofa diameter equal to said inner diameter between said large end of saidfilter and said valve seat, said housing further having a cylindricalportion of said outer diameter of said housing extending away from saidseat opposite said passage; and a valve closing member in said housingcooperating with said seat.
 2. The check valve defined in claim 1,further comprising a spring in said housing, braced against said housingand bearing upon said member.
 3. The check valve defined in claim 2wherein said filter is formed with elongated slits lying alonggeneratrices of a frustocone forming said filter, said member beingprovided with a sealing ring engageable with said seat, and said housinghas a peripheral groove receiving a further ring.